OP
Etymology 1
Noun
op (plural ops)
(informal) An operation.
(informal) An amateur radio operator.
(internet) An operator on IRC, who can moderate the chat channel, ban users, etc.
(mostly, attributive) Op art; a style of abstract art.
Verb
op (third-person singular simple present ops, present participle opping, simple past and past participle opped)
(transitive, Internet) To promote (an IRC user) to an operator.
Antonym: deop
Etymology 2
Noun
op
(internet slang) Alternative letter-case form of OP (“original post, original poster”)
Anagrams
• P.O., PO, Po, p.o., po, po'
Noun
OP (countable and uncountable, plural OPs)
Initialism of Overall Position.
Initialism of online pharmacy.
(theatre) Initialism of opposite prompt; stage right,
(Internet) Initialism of original poster; the person who started a thread.
(Internet) Initialism of original post.
(military) Initialism of observation post.
(organic chemistry) Abbreviation of organophosphate.
Initialism of opening credits.
Initialism of opening theme.
Antonyms
• (opening credits): ED
• (opening theme): ED
Adjective
OP (not comparable)
(publishing) Abbreviation of out of print.
Abbreviation of overproof.
(video games) Abbreviation of overpowered.
(Internet, music) Initialism of overplayed.
Synonyms
• (out of print): OOP
Antonyms
• (overpowered): underpowered, nerfed
Proper noun
OP
(religious) Initialism of Ordo Praedicatorum (Order of Preachers, the Dominicans, a religious order).
Anagrams
• P.O., PO, Po, p.o., po, po'
Source: Wiktionary